Iris x robusta ‘Gerald Darby’

Gerald Darby Iris

Iris x robusta is a designation for a hybrid of two native American irises, Iris versicolor and Iris virginica. ‘Gerald Darby’ is noted for its violet-blue flowers and dusky purple spring foliage. This plant is touted for its use in sunny sites near ponds, water gardens and moist borders.

Flower Description and Bloom Time
Purple flowers with yellow-splashed sepals (falls) appeared on purplish-black stems. Flowering began in early June and persisted for about two weeks. One evaluator recommended removing the spent flowers in midsummer.

Foliage Interest — Color and Texture
In spring, the leaves are a dusky purple tipped with green. Although one evaluator noted that the iris, which was planted in part shade, did not exhibit purple leaves, another found the purple leaves “very desirable.”

Habit and Growth Rate Observations
Plants ranged in size from 8 to 24 inches wide and 24 to 35 inches tall. Some plants flopped by midsummer. Several plants were slow to establish.

Site Preference — Soil and Light
Grow this plant in medium to wet soils in full sun to part shade. It may be grown in 2 to 4 inches of shallow standing water or a very moist border.

Successes and Possible Drawbacks
Soils must be consistently moist and should not be allowed to dry out. Site in full sun, moist soil and mulch with leaf mould.

Notes from Growers/Retailers
N/A

Good Combinations
Can be combined with any other moisture- and sun-loving plants, such as hibiscus, swamp milkweed and canna lilies.

Parting “SHOT” — The overall evaluation results were poor. *
This plant was evaluated from 2012 to 2015 at four sites in Chicago’s western and far northwestern suburbs with a total of 12 plants in the trial. By the third year of the evaluation, only five of the 12 plants survived. Although the evaluators did not recommend this plant, some noted that the lack of overall vigor may have been due to the size of the transplants and their small root systems. One of the four evaluators recommended the plant for its purple spring foliage that held onto its color into mid-summer as well as for its attractive flowers. evaluated 2012-2015